1. Field of the Invention
The present invention relates to methods and systems for testing disk drives, and more particularly, to a multi-cell disk drive test system used to test disk drives and that provides a power recovery mode.
2. Description of the Related Art
A huge market exists for disk drives for mass-market computing devices such as desktop computers and laptop computers, as well as small form factor (SFF) disk drives for use in mobile computing devices (e.g. personal digital assistants (PDAs), cell-phones, digital cameras, etc.). To be competitive, a disk drive should be relatively inexpensive and provide substantial capacity, rapid access to data, and reliable performance.
Disk drives typically employ a moveable head actuator to frequently access large amounts of data stored on a disk. One example of a disk drive is a hard disk drive. A conventional hard disk drive typically includes a head disk assembly (HDA) including at least one magnetic disk (disk), a spindle motor for rapidly rotating the disk, and a head stack assembly (HSA) that includes a head gimbal assembly (HGA) with a moveable transducer head for reading and writing data. The HSA forms part of a servo control system that positions the moveable transducer head over a particular track on the disk to read or write information from and to that track, respectively. Further, a conventional hard disk drive generally includes a printed circuit board assembly (PCBA) for the electronics of the disk drive.
Typically, a conventional hard disk drive includes one or more disks in which each disk has a plurality of concentric tracks. Each surface of each disk conventionally contains a plurality of concentric data tracks angularly divided into a plurality of data sectors. In addition, special servo information may be provided on each disk to determine the position of the moveable transducer head. The most popular form of servo is called “embedded servo” wherein the servo information is written in a plurality of servo sectors that are angularly spaced from one another and are interspersed between the data sectors around each track of each disk. Each servo sector typically includes a preamble generally having at least a track identification (TKID) field and a sector ID field and a group of servo bursts (e.g. an alternating pattern of magnetic transitions) which the servo control system of the disk drive samples to align the moveable transducer head with or relative to a particular track for the reading and writing of data.
During disk drive manufacturing, the disk drive typically undergoes a variety of tests and procedures to configure and validate the proper operation of the disk drive. Such testing is conventionally carried out in a multi-cell disk drive test platform that includes a bank of cells into which the disk drives are loaded and unloaded such that a sequential series of tests and procedures can be administered to the loaded disk drives. Some of the tests and procedures are subject to strict environmental control requirements. A wide variety of procedures, such as loading software and firmware, and tests, such as testing the servo control system, may be performed.
Because disk drive testers and disk drive testing represent such large expenditures for disk drive manufacturers, more efficient testers and testing procedures are continuously sought after in order to reduce inefficiencies and costs and to increase disk drive throughput.
One particular source of inefficiency associated with conventional multi-cell disk drive test systems is that, during a power failure, the entire multi-cell disk test system re-sets and each test process being performed at each cell is re-started again from beginning of the test process. This results in a great deal of wasted time and therefore additional costs are added to the disk drive manufacturing process. Accordingly, it is desirable to more efficiently deal with the occurrences of power failures during disk drive testing.